(a) Field of the Invention
The present invention relates generally to a motorized control for a derailleur, and more particularly to a derailleur which may be operated by pressing switches on the handlebar to achieve change of speed of bicycles in an easy and safe way.
(b) Description of the Prior Art
In conventional bicycles with derailleur, as a general rule, a cable is provided to control the chain to wind round different gears to achieve change of speed. The cable is connected to a shifter at the handlebar. By moving the shifter, the cable may be pulled taut or released so as to control the chain to fit onto the gear of a different diameter. But since the cyclist has to grip the handlebar in order to keep balance, control of the shifter when riding may be difficult and dangerous.